Signaling system for electric railways.



PATENTED' OCT. 15, 1907.

L. H. THULLEN. SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

APPLICATION PILED APR. 30, 1907.-

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@ 01 in cows No. 868,231. IATENTED OCT. 15, 1907. L. H. THULLEN.SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

APPLICATION IILBD APR. 30, 1907.

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witnesses SIGNALING SYSTEM FOR ELECTRIC RAILWAYS Specification ofLetters Patent.

Patent/.1 Oct. 15, 1907.

vp tfltieu filed April 30,1907. Serial N2 371.]61.

To all u'liom. if may c mma:

Be it known that l. liot'ts II. Tlll'LLl-ZX. a citizen oi th UnitedStates, r siding at Edg w d Park. in the county of Allegheny and tateot' Pcnnsylvania. havi invented certain new and useful lllll i t'tllllll in nignaling Systems for Electric ltailways. i which the f llowingis a specilicatiori.

.\ly invention relates to signaling sy t ms {or el ctric railway and hasfor an object the prevent ion f an improper operat ion of a railwaysignal [or one track by the signaling current from an adjacent track.scribe a signaling system embodying my invention and then point out thenovel features thereof in claims.

In the accompanying drawings. Figure i is a diagrammatical vi w of aportion of a double track railway, the rails of each track being dividedby insulation to form block sections and all the track rails beingincluded in the return circuit for the car propulsion current and havingapplied thereto a signaling system. emhodying my invention. Fig. 2 isaview similar to Fig. 1, but showing a modification oithesignalingsystem due to its being applied to a railway wherein an alternatingcum-at is (ttlpltr \'t-tl for car pr pulsion purposes. Figs. 3 and 4 areeach detail diaarat'uniatical views showing different forms of relayswhich may be used in the signaling system. Fig. 5 is a detailperspective view.

In Fig. 1 the signaling system is applied to an electric railw ay usinga dir ct current for ear propulsion purposes. In Fig. 2 th signalingsystem is applied to an electric railway using an alternating currentfor car propulsion purposes. I have not illustrated the director alt'rnat iug car propulsion systems in these figures as such syst ems arewell known and understood in the art. Th r lays diagrammaticallyillustrated in Figs. 3 and 4 are applicable more particularly insignaling systems applied to electric railways using alternating currentfor car propulsion purposes.

Similar letters of reference designate corresponding parts in all of thefigures.

Referring to the drawings, A, A, designate portions of two parallelrailway tracks of an electric railway, each of which is dividedbyinsulated joints a to form block sections. As shown, both rails of eachtrack are provided with insulated joints 0 to form block sectionsthough, if desired, only one rail of each track may be so divided. Botharrangements are well known in the art. In Figs. 1 and 2, I have shownone block section X and portions of two others Y, Z. in one railwaytrack, and one block section X and portions of two others Y,

Z, in the other railway track.

As the both rails of each railway track are included in the return pathfor the car propulsion currentand are suitably connected, one pole ofthe generator for the car propulsion current, which as stated, may beeither direct or alternating, provision is made for conducting thepropulsion cuirent around insulation points by means f reactance bonus.

I will d tn the drawings I have diagrammatically illustrated what. isknown in the art as the "balanced type'ioi reaetance bonds. B designatessuch bonds. Th se bonds, it well known, comprise a core or winding allthe turns of which are in the same direction and in close inductivrelation. Such a type of bond is set forth in L'. Patent No. 838,916,granted to me on D cember l 1906. In this type of head the pr wpulsiencurrent is made to tlow through two equal parts of the winding or twowindin s oi the some nuin her of turns in reverse directions, so thatthe propulsion current produces no magnetizing effect on the core,

III

- thus leaving the bond free to act as irnpcdances for the alternatingsignaling current of the track circuits. As shown. the windings of twoadjacent bonds are connected by a conductor [1 or there may be aplurality of such conductors. (ross bonds b are also provided betweenthe two railway tricks wher -v er possible, and they are for the purposeof reducing the resistance in the return circuit for the car propulsioncurrent. In the drawings I have shown the cross bonds b as beingconnected with the conductors b of the two railway tracks.

The signaling system applied to the railway, comprises a railway signalor signals, for each block seclimit. and a track circuit for each blocksection to control one operation or the railway signal or signals. S, S,3-. 5, etc., designate two railway signals which may he any of the wellknown types 0i automatic signals.

Each track circuit comprises a source of alternating current and a relayor relays. The source of alternating current let each track circuit isshown in the form of a transformer T, the secondary of which isconnected with the track rails of its block section while the primarymay he in multiple circuit with mains extending from a. suitablegenerator. The signaling current is preferably of a high frequency(6001' more cycles). The signaling current of the signaling system is ofa. different frequency from the alternating propulsion current when thesignaling system is applied to electric railways using alternatingcurrent for propulsion purposes.

Referring now to Fig. 1, each track circuit is provided with a relay R,but in addition to this relay R, a second relay R is provided to controlthe railway signal. The relay R is connected with the track mils of itstrack circuit in the usual manner and when energized by the alternatingsignaling current of its track circuit its vane r is moved to closecontacts in the signaling circuit. The relay R, however, is normallydeenergized, and its vane 1' is usually held h gravity or otherwise insuch position to close its contacts in the signaling circuit. With nocar or train i' a block section the apparatus will be in the conditionillustrated and the signal device s of the railway signal will he in itsclear position of indication. Should a car or train enter a blocksection, the wheels and axles thereof would short circuit thealternating signaling current from the relay R, which being denergized,its vane would move to open the signaling circuit and thus permit thesignal device of the railway signal S to move to indicate danger. Whenthe car or train moves out of the block section the relay R is againenergized to clos the signal circuitv These operations are wellunderstood in the art. It. will be ecu that the relay R had no part inthe operations just described. Its only purpose is to open the signalingcurrent in which it is included, should for any cause alternatingsignaling: curr nt from an adjacent track circuit tind a path throughthe cross bonds and conductors connecting the windings on adjacentreactauce bonds to the track cir--. ceit of relay R with which the relayR is associated. With normal or tlie'usual conditions existing underwhich the signaling system operates. the alternating signaling currentfor the several track circuits will be confined thereto and there is notendency for it to flow in paths other than the track circuits. Butsuppose that a rail of one block section was broken. for example. at thepoint- 0 in Figs. 1 and 2: Alternating signaling current from thetransformer T of block section X would then flow along the rail :1? tothe bond B at tinleft oi the figures. Half the potential of thetransformer would exi t at the middle point of the winding of the bond.and alternating signaling current. will flow through the adjacent crossbond b to the rails of block s-.-ction X. bond B at the right of blocksection X adjacent cross bond 1), bond B at the right of bloc'lt sectionX and the track relay R. imposing on this relay an electro-rnotive iorcewhich may be sufiicient to energize this relay should it have beenshortcircuitcd by a train in its block section, thus causing it to moveits vane and close the signal circuit. to have the railway signal clearwith a train in the block section. To avoid this wrong clearing of thesignal by this leakage current described. I have provided the relay Rand the tl'thsir rmer P. shown in detail in Fig. 5). This transfc'ineror inductive apparatus comprises a laminated in 11 core P. and asecondary winding P" which is in circuit with the relay It. The core Pis placed adjacent aconductor 1) as shown so that when the stray 0rleakage alternating current traverses the conductor b it will generate acurrent in the secondary winding P which causes the relay R to move itsvane to open itt signal circuit. Thus. should a track relay beimproperly energized by alternating signaling current from an adjacenttrack circuit the apparatus (transformer P and relay It) acts to open orkeep open the signal circuit The relays R, R, may be substantially ofthe form illustrated and described in U. S. Patent No. 823.086. issuedJune 12, 1906, to me.

Fig. 2 illustrates the same arrangement of circuits and apparatus, but adifferent type of relay R for each track circuit and the same type ofrelay ll for opening th signal circuit should a foreign signalingcurrent nter the track rails of the relay R with which it is associated. This relay per or forms no part of my invention, but is merelyshown as a preferable type of relay in an alternating signaling systemfor railways using an alternating current for car propulsion purposesand the track rails as part of the return path. The relay comprison asubstantially Wshaped core and an energizing winding on its middle leg.On one of its outside legs a closed conductor 1 is employed, which, whenan al ternating current of high frequency traverses the winding on themiddle leg exerts a counter-magneto force, thereby making the otheroutside'leg r a stronger pole to attract the armature. The armature ofthe relay R is balanced to close the signal circuit when no high irequency current is flowing in its energizing winding 1'". When the strayalternating signaling current traverses the winding on the middle leg,the armature of the relay R is moved to open the signal circuit.

Fig. 3 illustrates a further modification, the modification residingprincipally in the form of relay R. The relay is substantially like thatillustrated in the patent liereinbefore referred to except that anadditional core r and coil r is employed, which coil is in circuit withthe transformer P. The core 1' and coil 1' are so arranged that whenenergized by a stray alternating signaling current it will move the vaner to open the signal circuit, or if the vane has moved to open thesignal circuit it will act to hold the vane in that position as the samestray alternating signaling current will traverse both coils of therelay simultaneously. The coil T is in circuit with the track rails andthis coil is used to move the vane r to close the signal circuit whenenergized by current from the transformerT. The normal operation of therelay R is the same as that described in connection with' the relay R ofFig. 1. The form of invention illustrated in Fig. 3 is applicable moreespecially to electric railways employing direct current as a motivepower for the motor cars.

Fig. 4 illustrates a still further modification, the modificationresiding principally in the form of relay R The relay R is substantiallythe same as that illustrated in Fig. 2. In Fig. 2 two relays (R R areused whereas in Fig. 4 only one relay is used. The operation of therelay R" under usual conditions is the same as that described inconnection with the relay R of Fig. 2; When a stray alternatingsignaling current flowsover the conductor 12 and induces a' current inthe windin P of the device P, it magnetizesthe leg 1 of the relay by thewinding 1 and causes the armature r to move to open the signal circuit.

Having thus described my invention, what I claim 1. The combination withtwo parallel tracks of an electrlc railway the ralls of each trackwaybeing dlvlded to form block sections and are used to conduct carpropulsion current to the generator thereof, of reactance bonds placedacross the rails of each trackway, a conductor connoctlnz adjacent bondsin the same track-way, cross bonds between such conductors. a blocksignaling system for each track way employing an alternatlng signalingcurrent in the track circuits of the signaling system. means adjacentthe said conductors in which a current is induced by a stray alternafln:signaling current flowing over such conductor. and means affected bysald induced current for opening a signal circuit.

2. The comblnatlon wltltwo parallel tracks of IV] elec' tric railway therails of each trackway being dlvl-led t form hlock sections and are usedto conduct car: propulsldu current to the generator thereof, atreactance bonds p aced across the rails of each trackway, a conductorconnecting adjacent bonds in the same trackway. cross bonds between suchconductors. a block slgnallng system tor each track way employing analternating signaling current In the track clrcults of the slgnallngsystem, means adjacent the said conductors ln which a current ls Inducedby a stray alternating slgnallng current flowing over such conductor,and a relay affected by said induced current for opening a signalcircuit.

10 adjurcnt the said conductors in which a current is induced by a strayalternating signaling current flowing over such conductor, and a relayaffected by said induced current for opening a signal circuit.

In testimony whereof I have signed my name to this specification in thepresence of two subscribed witnesses. 15

LOUIS H. THULLEN.

Witnesses: ELMER R. Con, DANIEL J. MCCARTHY.

